Model N901 THC/CH4/NMHC

The Model N901 is a near-continuous hydrocarbon gas analyzer that measures the concentration of Methane (CH4) and Total Hydrocarbons (THC) in air. The concentration of the non-Methane (NMHC) component is calculated by the subtraction of CH4 from THC, with high sensitivity and accuracy. The hydrocarbons are measured using a Flame Ionization Detector (FID), in combination with gas chromatography (GC). The instruments range and performance are tuned specifically for use in ambient air quality monitoring assessments.

The Model N901 is designed for simple operation and maintenance with a modular hardware and electronics architecture.  A long-life stainless-steel fritted filter is used at the sample intake to effectively remove particulate matter without introducing any gas-phase measurement artifacts. Instrument operation, calibration functions, chromatogram views,​ and data handling are all automated and controlled using the internal NumaView™​ Software (NVS) interface, without the need for an external PC.​

For remote connection to the N901 instrument, Teledyne API’s NumaView™ Remote PC-based Software provides a virtual interface, instrument controls, and data downloading capability to all TAPI analyzers operating NumaView™ Software.


  • ​60s default cycle time
  • 25 ppb LDL (CH4, NMHC) ​
  • Fully programmable and automated directly from the instrument front panel interface
  • Modular internal hardware design for ease of maintenance
  • All internal components operate on 24VDC
  • Front panel USB connections for peripheral devices and firmware upgrades
  • Real-time chromatogram display during calibration routine
  • Real-time graphical displays of concentrations and diagnostic parameters
  • Comprehensive internal datalogging with programmable averaging periods
  • Ethernet and Serial outputs, standard
  • Analog output and digital I/O expansion (options)
  • Internal pressurized span valve for auto calibration (option)​​
Detector Flame Ionization Detector (FID)
Method Gas Chromatography with CH4 separation column
Ranges (Methane) Min: 0-5 ppm
Max: 0-1,000 ppm
Lower Detectable Limit <25 ppb (Methane); <25 ppb (Propane)
Cycle Time 60 sec (minimum), user-definable
Precision <1% of reading or 0.05 ppm (whichever is​ greater)
Linearity ​<1% of full scale
Zero Drift Zero baseline performed once per cycle
Span Drift (24hr) <1% of full scale
Sample Flow Rate 60 cc/min + 10%
Carrier Gas 50 to 70 psi​, N2 UHP Grade, Consumption 20 cc/min
Fuel Gas 50 psi ± 5%, H2 UHP Grade, Consumption 35 cc/min
FID Air 50 psi ± 5%, HC Free clean air, Consumption 350 ​cc/min
Auxiliary A​ir 70 psi ± 5%,​ Clean Dry Air, Consumption 1 cc/actuation
Included I/O 1 x Ethernet (TCP/IP)
1 x RS232
2 x front panel USB device ports​
Optional I/O Universal Analog Output Board includes (all user-definable):
4 x Isolated Voltage Outputs (5V, 10V; user-selectable)
3 x Individually Isolated Current Outputs (4-20mA)
​Digital I/O Expansion Board includes:
3 x Isolated Digital Input Controls
5 x Isolated Digital Output Controls (user-definable)
3 x Form C Relay Alarm Outputs (user-definable)
Dimensions (HxWxD) 7” x 17” x 23.5” (178 x 432 x 597 mm)
Weight 35 lbs (16 kg)
Operating Temperature 7​5-40°C
Power 100-240V, 50/60Hz, Typical Power 130W​
Warranty Two years




Ambient Monitoring

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